The present invention relates to fastener driving tools, and more particularly to pneumatically powered fastener drivers, also referred to as pneumatic nailers.
In conventional pneumatic nailers, such as those disclosed in U.S. Pat. Nos. 3,638,532; 6,604,664 and pending application Ser. No. 13/037,872 incorporated by reference, the nailer is pressed down upon a workpiece needing a fastener, and in so doing, a workpiece contact element (WCE) is retracted relative to the tool housing. User depression of a trigger activates a trigger valve, which directs pneumatic pressure within the tool such that a piston is driven down a sleeve or cylinder to impact and drive a fastener into the workpiece.
Pneumatic nailers have traditionally been equipped with sleeves or cylinders made of metal, such as cast aluminum or the like. Due to a motivation for reducing cost and weight for such tools, sleeves made of plastic have been used with some success in relatively smaller pneumatic nailers such as trim tools and staplers. Such sleeves are preferably made by injection molding. These tools generate relatively less energy than that generated in a relatively larger framing tool. Due to the increased operational stresses and power generated by framing tools, plastic sleeves have not previously been suitable, and have failed when applied to such tools. However, there is still a desire by manufacturers to provide pneumatic framing tools with the advantages of reduced cost and weight obtained by smaller tools in converting to plastic sleeves.